KR100299907B1 - Broadcast packet transfer method in lan emulation and an lsi device for same - Google Patents

Abstract

A method for transferring data between circuits in a broadcast-and-unknown server (BUS) and a bus device of a LAN emulation system, wherein an AAL5-LSI (ATM conforming layer (5))-LSI device is a receiving VPI / VCI (virtual path identifier). / Virtual channel identifier) and an interface memory capable of storing a correlation between the transmission VPI / VCI of the simultaneous transmission packet data are provided, and this correlation is established from the bus. The destination of the simultaneous transmission packet received from the circuit is determined based on this interface memory, and according to this determination result, the simultaneous transmission packet received from the circuit is directly transmitted back to the circuit side by the AAL5-LSI, and not via BUS. Do not. This bus establishes a correlation between the receiving VPI / VCI and the transmitting VPI / VCT in interface memory when the connection is installed as a LEC (LAN Emulation Client) and cancels the correlation when the connection is lost.

Description

BROADCAST PACKET TRANSFER METHOD IN LAN EMULATION AND AN LSI DEVICE FOR SAME

The present invention provides a broadcast packet transmission method and a broadcast packet transmission method in LAN emulation for a local area network (hereinafter simply referred to as "LAN") of an asynchronous transmission mode (hereinafter referred to simply as "ATM") system. Apparatus, and in particular, a high-speed transmission method of broadcast packets by a BUS (Broadcast-and-Unknown Server, simply "BUS") in LAN emulation, and a large scale integration (LSI) device used to realize such a transmission method. It is about. Also, in this specification, a broadcast packet includes not only multicast packets sent to all other nodes or terminals, but also unknown packets searching for a specific group destination or a specific server.

The LAN emulation method is proposed as a method for accommodating existing LANs in ATM networks, and the specification of this method was published in the LAN Emulation Over ATM Specifications, 1.0 edition by the ATM Forum 94-0035R4, LAN Emulation SWG Drafting Group.

This LAN emulation method is performed by a client called a LAN emulation client and a server or a bus such as a LAN emulation server (hereinafter simply referred to as LES).

The LES is a server that searches for ATM addresses required for communication based primarily on the Media Access Control (MAC) address of the Ethernet interface hardware. The BUS primarily controls the transmission function of broadcast packets, including multicast packets or unknown packets in existing LAN media such as Ethernet.

There are three types of methods for transmitting broadcast packets. The first method is to send packets to all terminals / nodes at once, using the address unique node numbers for all modes added when generating an address for transmission, and refer to that address at the transmission destination, to the added address. Packets are only taken from terminals / nodes with matching node numbers. The second method searches for a location in an ATM-LAN system that provides a particular service, so that if all terminals / nodes receive a particular broadcast packet for that purpose, the address is all "1". The third method is to set all addresses to "0" if the connection establishment process is aware of the connection status of the system and sends a specific broadcast packet only to terminals / nodes that are directly connected to the source terminals / nodes by the physical link. do. In an ATM-LAN system, a connection in an ATM communication network is established mainly within the ATM layer, so that the terminal connected to this ATM-LAN system is network-side when "discovering a host to use a particular service". You have to depend on the function. In view of this, Japanese Patent Laid-Open No. 202905/95 discloses a design for the purpose of increasing the independence of terminals from network side functions.

However, the broadcast packet transmission method by LAN emulation of the prior art is configured to transmit broadcast packets, multicast packets, and unknown packets only by BUS, and the BUS transmission performance in this case is 10,000 packets / sec. It is not expected to exceed.

From the hardware point of view, the transmission capacity of the internal bus of the BUS device is a bottleneck, while in the software aspect, there is a problem with the LSI drive and the BUS performance. To achieve high-speed transmission of broadcast packets, It is necessary to greatly increase the data processing speed of the BUS. However, improving the transmission performance of the internal bus and the data processing speed of the BUS make the construction of prior art systems very difficult.

It is a first object of the present invention to provide a method for enabling high-speed transmission of broadcast packets in LAN emulation regardless of the performance of the internal bus or the speed of data processing in the BUS device.

It is a second object of the present invention to provide an LSI apparatus capable of performing high-speed transmission of broadcast packets.

1 is a block diagram showing a configuration of Embodiment 1 of the present invention;

2 shows a hardware function of the BUS device.

3 shows an example of the contents of an interface memory with a BUS in AAL5-LSI;

4 shows an example of a connection between an ELAN and a BUS;

5 is a diagram showing an example of setting of a BUS interface memory.

※ Explanation of code for main part of drawing

10: BUS main part 20: signal part

30: SSCOP 40: AAL5-LSI Driver

50: AAL5-LSI 60: circuit interface

70: physical circuit 80: BUS device

In order to achieve the above object,

Broadcast packet transmission method of the present invention,

Providing an interface memory in the data transmission means between the BUS and the circuit and capable of storing a correspondence between the transmission VPI / VCI of the broadcast packet data set from the BUS and the reception VPI / VCI (Virtual Path Identifiers / Virtual Channel Identifiers);

Determining, according to the VPI / VCI received from the circuit, the transmission destination of the packet data with reference to the interface memory;

According to the result of the determination, the broadcast packet received from the circuit is transmitted to the higher rank software or the address of the transmission VPI / VCI.

Further, when the BUS is connected to the LAN emulation client (LEC), it establishes a correspondence between the reception VPI / VCI and the transmission VPI / VCI in the interface memory, and releases the correspondence when the connection is lost.

The LSI device of the present invention used to implement the above-described method is an ATM Adaptation Layer 5 (ATM5, simply referred to as "AAL5")-LSI device having an interface with a BUS, and also receives a VPI / VCI of the BUS. It has an interface memory for setting the transmission VPI / VCI corresponding to BUS.

This AAL5-LSI device utilizes a point-to-multipoint switch virtual connection (hereinafter simply referred to as "SVC") established from the BUS to a virtual channel connection of multicast forwarding (hereinafter simply referred to as "VCC"). Multicast transmissions using point-to-point SVC from multiple LESs, together with one transport VPI / VCI for all emulated LANs (hereinafter simply referred to as “ELANs”), and ELAN as devices, specified by Communicates according to multiple received VPI / VCIs for all LESs designated by VCC,

By setting the correspondence in the interface memory, one transmit VPI / VCI for all ELANs to which the LEC belongs corresponds to the number N of received VPI / VCIs for all LECs.

When AAL5-LSI receives the broadcast packet data, the AAL5-LSI circuit may be determined by the transmission VPI / VCI if the correspondence between the reception VPI / VCI and the transmission VPI / VCI is set in the data after referring to the interface memory. The data is sent directly to the network, and if no correspondence is established, the data is passed to higher-level software.

According to the above-described method and the apparatus of the present invention, the broadcast packet transmitted by the BUS in the ELAN device can be directly transmitted by the AAL5-LSI device instead of the BUS, and may not be transmitted by the BUS. As a result, the transmission speed is less limited by the characteristics of the internal bus, and high speed transmission can be achieved several ten times faster than the prior art method.

Hereinafter, other objects, features, and advantages of the present invention will be described in more detail with reference to the accompanying drawings showing examples of preferred embodiments of the present invention.

In FIG. 1, the BUS device 80 includes a BUS main section 10, a signaling section 20, a service specific connection adaptation protocol (hereinafter simply referred to as "SSCOP") 30, an AAL5-LSI driver 40; AAL5-LSI 50, circuit interface 60, and physical circuit 70.

Signaling 20 establishes a point-to-point switch virtual connection (hereinafter simply referred to as “SVC”) or a point-to-multipoint switch virtual connection (SVC) and interfaces with BUS 10. do.

SSCOP 30 is a type of layer-3 procedure defined by Recommendation Q2110, which is a Service Specific Connection Adaptation Protocol (SSCOP) of the B-ISDN ATM adaptation layer, which is sent when data is lost or there is an error in the data content. It is a protocol that controls the function.

AAL5-LSI driver 40 is a driver with an interface function between AAL5-LSI and higher ranking software.

The AAL5-LSI 50 is an LSI for data transmission service having a function of combining and packetizing cells when receiving a cell and separating and transmitting the packet into cells when transmitting a packet.

In view of the hardware functions of the BUS device, as shown in Fig. 2, the CPU, the memory accessed by the CPU (CPU memory), and the AAL5-LSI are connected to the internal bus. The AAL5-LSI comprises an AAL5-LSI memory and an AAL5-LSI control unit in which the BUS interface-memory of the present invention is integrated, and is additionally connected to the optical cable by a circuit interface. BUS 10, signal portion 20, SSCOP 30 and AAL5-LSI driver 40 of FIG. 1 are stored in the CPU memory, and the CPU uses these elements to communicate with AAL5-LSI via an internal bus. use. The correspondence between the receiving VPI / VCI and the transmitting VPI / VCI from the BUS is stored in the BUS interface-memory.

Hereinafter, the operation of the present invention will be described with reference to FIG. 3.

When receiving data from the circuit, the AAL5-LSI 50 refers to the BUS interface-memory, and if "NULL" is represented by the received V PI / VCI number, a request is made to transfer data from the BUS to the circuit. The circuit treats this data as none, causing it to pass on higher-ranked software, and if it is not "NULL", decode it as a transfer request from the BUS and take the data to its transmit VPI / VCI value. Transmit the data directly to the circuit using the transmit VPI / VCI.

In practice, if not NULL, the LEC sends broadcast packets to the BUS using a connection of a multicast transmitting virtual channel connection (VCC), and the BUS sends these broadcast packets to an ELAN using a multicast forward VCC connection. Send to all LECs contained within.

Here, the multicast transmission VCC is a point-to-point SVC set from the LEC to the BUS direction, and the multicast forward VCC is a point-to-multipoint SVC set from the bus to the LEC direction.

When the multicast forwarding VCC is set to LEC, the BUS sets the correspondence between the received VPI / VCI values and the transmitted VPI / VCI values in the BUS interface memory via the AAL5-LSI driver, and in addition, the multicast forwarding VCC Is released, set "NULL" in the BUS interface memory via the AAL5-LSI driver to release this correspondence.

In FIG. 4, if LEC 11 and LEC 12 are included in ELAN 10, LEC 21 and LEC 22 are included in ELAN 20, and are connected to buses 101, 102, 201. And 202 are multicast transmission VCCs with LEC 11, LEC 12, LEC 21 and LEC 22, respectively, and connections 301 and 302 are connected to ELAN 10 and ELAN 11, respectively. It is a multicast forward VCC directed to the LEC to which it belongs.

The connection 301 is a point-to-multipoint SVC set up from the BUS in the direction of LEC 11 and LEC 12, belonging to the ELAN 10, and the connection 302 belongs to the ELAN 20 from the bus. Point-to-multipoint SVC set in the LEC 21 and LEC 22 directions.

Meanwhile, in the present specification, the VPI / VCI value is represented by 0 / i ', where i' is an index value of the BUS interface memory as described with reference to FIG. 5 below.

In this case, 0/32, 0/34, 0/35, 0/37, 0/33 and 0/36 represent the specific VPI / VCI values for connections 101, 102, 201, 202, 301 and 302, respectively. Yes.

Next, with reference to FIG. 5, a description will be given of a method of using a BUS interface memory for the case where ELAN and BUS are connected as shown in FIG.

When the received VPI / VCI is 0 / i ', the index value of the BUS interface memory is i', and the initial values of the BUS interface memory are all "NULL" values.

When connection 101 is established, the BUS sets the point-to-multipoint SVC to LEC 11. At this time, the transmission VPI / VCI of the connection 301 is set to 0/33 at the position corresponding to the index value 32 of the BUS interface memory. When connection 102 is established, the BUS sets the point-to-multipoint SVC to LEC 12, and the transfer VPI / VCI goes to 0/33 at the position corresponding to the index value 34 of the BUS interface memory. Is set.

In addition, the setting regarding the ELAN 10 is also set by the above-described process.

In the same way, the transmission VPI / VCI is set to 0/36 at the position corresponding to the index values 35 and 37 of the BUS interface memory, thus affecting the setting regarding the ELAN 20.

When the connection is broken, the BUS sets the corresponding BUS interface memory to "NULL". For example, when the connection 101 is cut off, the position corresponding to the index value 32 of the BUS interface memory is set to "NULL".

According to the present invention, the AAL5-LSI having an interface with the BUS transmits data received by the receiving VPI / VCI at 0/32 and 0/34 in the transmission VPI / VCI at 0/32 with reference to the BUS interface memory. In the same way, the data received by the receiving VPI / VCI of 0/35 and 0/37 is transmitted from 0/36 to the transmitting VPI / VCI. Also, when data is received with the data set in the BUS interface memory corresponding to the received VPI / VCI set to " NULL ", the data is transferred to the AAL5-LSI driver, i.e., higher order software.

It is apparent that variations and modifications of the method of transmitting broadcast packets in the LSI apparatus and the LAN emulation for realizing the method disclosed herein can be made by those skilled in the art. It is intended that the present invention include all such modifications and variations within the scope of the appended claims.

As described above, according to the present invention, the broadcast packet transmitted by the BUS in the ELAN device may be directly transmitted by the AAL5-LSI device instead of the BUS, and may not be transmitted by the BUS. As a result, the transmission speed is less limited by the characteristics of the internal bus, and there is an effect of achieving a high-speed transmission several ten times faster than the prior art method.

Claims (7)

A method of transmitting broadcast packet data between a broadcast-and-unkonwn server (BUS) and an asynchronous transfer mode (ATM) network during local area network (LAN) emulation. Providing a correspondence table between reception VPI / VCI (Virtual Path Identifiers or Virtual Channel Identifiers) of the broadcast packet data and transmission VPI / VCI; Detecting a VPI / VCI of broadcast packet data received via the ATM network; Referring to the detected VPI / VCI in the correspondence table; Setting the broadcast packet data to the corresponding transmission VPI / VCI set in the table; And Transmitting the broadcast packet data directly to a network. The method of claim 1, A method of transmitting broadcast packet data, characterized in that a correspondence between the reception VPI / VCI and a transmission VPI / VCI is set in a table by a bus when a LAN emulation client is connected, and the correspondence is released when the connection is blocked. . The method of claim 2, By BUS, a correspondence relationship for providing one transmission VPI / VCI using multicast forward VCC is established for each ELAN corresponding to a plurality of reception VPI / VCIs from the LEC for each ELAN using multicast transmission VCC. The broadcast packet data transmission method, characterized in that. The method of claim 3, wherein The multicast transmission VCC is a point-to-point Switched Virtual Connection (SVC) from each LEC to BUS, And the multicast forwarding VCC is a point-to-multipoint SVC from a bus to every LEC of each ELAN. The method of claim 1, And when the correspondence is not set in the table, the broadcast packet data is passed to higher software. A device for transmitting broadcast packet data between a bus and an ATM network in LAN emulation, The BUS is, A driver for driving AAL5 by an interface between AAL5 (ATM Adaptation Layer 5) and higher software; Signal circuitry for establishing either point-to-point SVC or point-to-multipoint SVC; And Includes a circuit according to the Service Specific Connection Oriented Protocol (SSCOP), The device, An interface between the ATM network and the BUS; And And transmitting an AAL5 device having an interface memory for storing a correspondence table between a receiving VPI / VCI and a transmitting VPI / VCI, and transmitting the received broadcast packet data to an ATM network. Device. The method of claim 6, Wherein the AAL5 device is embedded in a large scale integrated circuit (AAL5-LSI).